Fix bug with embedded videos in BBC stories

The scraper was having trouble with BBC articles with embedded videos, because they don't have a "story-body" div element. I added a bit of code to try set the div element to the one holding the video description if there wasn't a "story-body" div, so the scraper can find the text in these cases.

The descriptions are usually short and content-lite, but I bet they could be interesting to track, too. For example, here's something from today:

![Gunned down](https://s3.amazonaws.com/zthomae-project-pics/gunneddown.png)